Method of making radiator core structures



Oct. 29, 1929. 1-, N. COFFELDER 1,733,646

' METHOD OF MAKING RADIATOR CORE STRUCTURE I Filed Aug. 5; 192a PatentedOct. 2 9, 1929 PATENT OFFICE THOMAS N. COFFELIDER, OI" PITTSBURGH,PENNSYLVANIA METHOD OF MAKING'BADIATOR CORE STRUCTURES Application filedAugust 3, 1928. Serial No. 297,134.

This invention relates to radiator core structures for automobiles andit is among the objects thereof to provide a radiator structure whichshall be of simple durable mechanical construction which shall be ofrelatively large cooling capacity and Which shall be eflicient in itsfunction for cooling the water in the engine jacket with which it isonnected. 4

In radiator structures heretofore proposed, the tubes throughwhich thecooling water is circulated, are provided with supporting fins ofvarious forms which are designed to conduct the heat from the tubes andto proride an open cooling structure of relatively large'surface areathrough which the cooling air passes by forced circulation. An importantfeature to the attainment of good heat (-oi'uluctivity from the tubes ofthe fins is intimate contact between these members and in mostconstructions such contact is made available by soldered connectionsbetween the joining elements and fin, the fin being part of the tube.

I have discovered that a soldered joint for radiator construction is notefficient for the conduction of heat from the circulating tubes andfurthermore such joints are readily broken by the vibrations andstresses to which the radiator is subjected in use.

In accordance with my present invention, I produce intimacy of contactbetween the fin and tube structures of radiators without the use ofsoldering in such manner that the metal of the tubes envelops thecontacting edges of the fins whereby intimate contact is assured. IViththis construction, a radiator cannot be damaged by freezing since thereis nothing to rupture as in the soldered connections of the commontypes.

In the accompanying drawing constituting a part hereof and'in which likereference characters designate like parts, Fig. 1 is a front elevationalview of a radiator structure embodying the principles of this invention;Fig. 2 a cross-sectional view taken along the line II-II, Fig. 3; Fig. 3a plan view partly in section and partly in elevation; Fig. 4 a sideelevational view between the tube and fin members; Fig. 5 an elevationalView ofthe fin; Fig. 6 an end view of the fin shown in Fig. 5; and Fig.7 a cross-sectional View of the fin and a section of the tubeillustrating the manner of their engagement in accordance with thisinvention.

In the structure shown in Fig. 1, the tubes 1 are made of copper stripswhich are rolled to form indentations 2 which when joined form the tubesor slotted openings through which the water circulates. A pair of thecopper strips form a single tube and they are arranged with their endsflanged as at 3, and alternate tubes, are disposed Wit-h their flangesoverlapping, as clearly shown in Figs. 1 and 2.

Ordinarily, the thickness of the tubing is about .005 of an inch but Ihave found that a heavy gauge metal is more satisfactory forconstructing radiators in accordance with my invention and I employsheet copper strips that are preferably from .006 to .007 in thickness.

. The fin structure is preferably of saw-tooth shape (Figs. 6 and 7) andis made of brass with indentations 4 which correspond in length to thewidth of the depressions 2 forming the tube structures so that whenthefins are assembled between adjacent tubes the depressed portions 4 liesnugly against the projecting portions 2 of the tubing. I prefer to formthe fin of saw-tooth form since I have found that this form of toothlends itself more readily to a readjustment of the structure afterfreezing, thus preventing rupture of the joints. After the tubing andfins are assembled in the manner shown in Figs. 1, 2 and 3, they areprovided with end chambers and the assembled structure after solderingat the flanged joints 3 and along the joining edges 5 of the tubes, issubjected to hydraulic 99 pressure ranging from 20 to 30 pounds. Thepressure in the tubes is effective in expanding the soft copper wherebythe outer walls of the tubesare forced against the edges of thefinsresulting in the copper enveloping the edges of the teeth of the finin the manner exaggeratedly shown in Fig. 7. The efiect of the pressureis such as to produce a riblike effect as at 7 which indicates thatintimate contact between the fins and tubes is obtained without the useI have found that with the copper and I brass contact, without anysolder interposed, the fin is more capable of conducting the heat fromthe tubes, thus producing a radiator structure of increased coolingefficiency which greatly increases the capacity of the radiator forcooling the water to the extent that a core section of lesser thicknessmay be employed for the practice of my invention than is possible withother forms'of radiator core structures.

If the radiator is subjected to freezing temperature, the tubes arepermitted to expand because of the flexibility of the saw tooth finwhich is capable of coming back to its original. form without rupturingthe con: nection with the tube. 7

It is evident from the foregoing description of this invention thatradiator core structures made in accordance herewith are relativelyinexpensive to manufacture and eflicient for cooling water circulatingtherein.

Although one embodiment of the construction has been herein illustratedand described it will be obvious to those skilled in the art thatvarious modifications may be made in the details of construction withoutdeparting from the principles herein set forth.

I claim herein as my invention:

1. The method of making radiator core structures which comprisesassembling a plurality of circulating tubes between cooling fins ofcorrugated form, joining the assembled tubes and fins to constitute aunitary structure, and subjecting said structure to the same against thecontacting edges of the said corrugated strips.

5. The method of makin radiator core structures which comprises ormingdepressions in strips of sheet copper, assembling said strips with theirdepressions adjacent one another to constitute tubes, assembling saidtubes between corrugated brass strips, constituting cooling fins, andsubjecting said. tubes to internal pressure to expand the same wherebythe tubes intimately contact with adjacent edges of said fins inthe-region of their depressions.

6. The method of making radiator core structures which comprises formingdepressions in strips of sheet copper, assembling said strips with theirdepressions adjacent one another to constitute tubes, assembling saidtubes between corrugated brass strips having their corrugationsflattened along the portions contacting with the depressions in saidtubes, and subjecting said tubes to internal pressure to expand the sameto produce intimate contact with the flattened edges of said brassstrips.

In testimony whereof, I have hereunto set my hand.

THOMAS N. COFFELDER.

internal pressure to expand the tubes against the contacting edges ofthe cooling fins.

2. The method of making radiator core structures which comprisesassembling a plurality of circulating tubes between cooling fins ofcorrugated form, joining theassembled tubes and fins to constitute aunitary structure, and subjecting said tubes to internal pressure toexpand the same against the contacting edges of the cooling fins.

3.The method of making radiator core structures which comprisesassembling a plurality of circulating tubes between cooling fins ofcorrugated form, joining the assembled tubes and fins to constitute aunitary structure, and subjecting said tubes to internal pressure offrom 15 to 30 pounds per square inch to expand the same against thecontacting edges of the cooling fins.

4. The method of making radiator core structures which comprisesformingdepressions in strips of soft sheet copper, assembling said strips withtheir'depressions adj acent one another to constitute tubes, assemblingsaid tubes between corrugated brass strips constituting cooling fins,and subjecting said tubes to internal pressure -to expand

